Many electrical systems employ devices that generate significant amounts of heat such as, for example, power semiconductor devices or other power electronics devices. For example, many motor drives, reduced voltage soft starters and other machinery employ power semiconductor devices such as, further for example, diodes, silicon control rectifiers (SCRs), insulated gate bipolar transistors (IGBTs), integrated gate commutated thyristors (IGCTs), and symmetrical gate commutated thyristors (SGCTs). In many if not all such electrical systems it is desirable if not necessary that the heat generated by such devices be substantially dissipated away from those devices and out of the systems in a reliable, efficient manner.
In some systems employing multiple power semiconductor devices, the various power semiconductor devices are integral with respective printed circuit boards (PCBs) that are positioned successively adjacent to one another within a larger power cage housing or other support structure, with the power semiconductor devices themselves being positioned in line with one another and with heat sinks being positioned in between the neighboring power semiconductor devices so as to form a stack or “press pack” of such alternating power semiconductor devices and heat sinks. One exemplary system with such a stack is shown in, for example, U.S. Pat. No. 6,532,154 assigned to Rockwell Automation Technologies, Inc., the beneficial assignee of the present application, which is hereby incorporated by reference herein.
Typically, in order to attain the highest degree of heat dissipation from the power semiconductor devices of such a stack, the components within the stack need to be axially aligned along the entire length of the stack such that adjacent planar surfaces of the heat sinks and power semiconductor devices are in contact with one another as much as possible, and so that pressure is as evenly distributed along those interfacing surfaces as possible, so that heat can be effectively transferred from the power semiconductors to the heatsinks. However, such axial alignment can be difficult to perfectly attain because, when the different cards of the system on which the power semiconductor devices and heat sinks are mounted are inserted into a power cage housing or other support structure for those components, the resulting pressures engendered among the various structures/components can result in their slight deformation.
More particularly, assuming that in such a system the cards supporting the power semiconductor devices and heat sinks are inserted into the housing in the same manner as books are inserted into a book shelf (that is, from a front side of the housing toward a back side of the housing), there can be deformation of the housing from the front to the back. When such deformation occurs, the alignment among adjacent power semiconductor devices and heat sinks extending along the length of the book shelf becomes imperfect, such that there can be variations in the pressures experienced at different contact locations between such adjacent surfaces. As a result, the dissipation of heat from the power semiconductor devices can be reduced by 10-15% or even more. In some circumstances, such reduced heat dissipation capability can put stresses upon the power semiconductor devices and/or other components and reduce their useful lifespan(s).
For at least these reasons, therefore, it would be advantageous if an improved system and/or method were developed for supporting heat-generating electrical devices such as power semiconductor devices or other power electronics devices in a manner that enhanced and/or maximized heat dissipation from those devices. In at least some embodiments involving stacks of devices, such as power semiconductor devices and heat sinks, it would be further advantageous if such an improved system and/or method particularly achieved support for those devices in a manner that facilitated proper alignment of those devices such that the contact between interfacing surfaces of adjacent devices was maximized and/or contact pressure along those surfaces was rendered more even. Additionally, in at least some embodiments, it would be advantageous if the implementation of such an improved system and/or method did not entail large space requirements.